Buildings and clothes could melt to save energy

It is no design flaw: encapsulated within the walls and ceiling panels is a gel that solidifies at night and melts with the warmth of the day. Known as a phase change material (PCM), the gel will help reduce the amount of energy needed to cool office space in the building - scheduled to house the molecular engineering department when completed this month - by a whopping 98 per cent.
— newscientist.com